Minimally invasive surgical tower access devices and related methods

ABSTRACT

Devices and methods are provided for assisting in spinal stabilization. An access device is provided that includes an outer sleeve, inner sleeve, spring latch and lock nut. The inner sleeve includes compressible grasping elements. The access device can be coupled to a screw head by sliding the outer sleeve relative to the inner sleeve and compressing the grasping elements. The coupled access device and screw can then be delivered to a target location in a patient. After providing two or more access devices, a rod member can be delivered using a rod insertion device. The rod member can serve as a connection between the two screws, and can provide spinal stabilization. An anti-torque device and a persuading device can be used to help ensure that the rod member is placed and secured in a proper location within a patient.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present application relates to devices and methods for providingspinal stabilization. In particular, the present application relates tominimally invasive devices and methods for delivering fixation devicesand implants into a spine.

2. Description of the Related Art

Spinal bone degeneration can occur due to trauma, disease or aging. Suchdegeneration can cause abnormal positioning and motion of the vertebrae,which can subject nerves that pass between vertebral bodies to pressure,thereby causing pain and possible nerve damage to a patient. In order toalleviate the pain caused by bone degeneration, it is often helpful tomaintain the natural spacing between vertebrae to reduce the pressureapplied to nerves that pass between vertebral bodies.

To maintain the natural spacing between vertebrae, spinal stabilizationdevices are often provided to promote spinal stability. These spinalstabilization devices can include fixation devices, such as spinalscrews, which are implanted into vertebral bone. The fixation deviceswork in conjunction with other implanted members, such as rod members,to form stabilization systems.

Conventional stabilization systems often require open surgeries andother invasive procedures in order to deliver the implants into thebody. These invasive procedures often cause a great deal of pain andtrauma to the patient, and require a substantial recovery time. Thus,there exists a need for minimally invasive devices and methods that canassist in providing spinal stabilization.

SUMMARY OF SOME EMBODIMENTS

Devices and methods are provided for assisting in spinal stabilization.In some embodiments, a system for spinal stabilization is provided. Thesystem comprises a percutaneous access device including an outer sleevehaving a proximal slot and a distal slot. The access device alsoincludes an inner sleeve having a proximal section and a distal section,the proximal section being operably connected to a spring latch having atab member and including a threaded portion, the distal sectionincluding a slot and a pair of compressible grasping elements, each ofthe grasping elements including slits, an internal tapered surface, andan internal protruding member capable of being received in an aperturein a head of a screw member, wherein the inner sleeve is configured tobe slidably received into the outer sleeve such that the spring latch islocated within the proximal slot of the outer sleeve and the slot of theinner sleeve is aligned with the distal slot of the outer sleeve. Inaddition, the access device can include a lock nut having an internalengagement surface for engaging the threaded portion of the innersleeve, wherein placement of the lock nut at a bottom section of thethreaded portion of the inner sleeve results in compression of thegrasping elements, and wherein the internal engagement surface isconfigured to interact with the tab member via depressions to limitcounter rotation of the lock nut during use.

The system can also include a cannulated screw member that is attachableto the inner sleeve. The cannulated screw member comprises a headportion coupled to a shaft, wherein the head portion includes a seat forreceiving a rod implant, one or more apertures for receiving an internalprotruding member of the inner sleeve, and at least one slot forinteracting with the internal tapered surface of the inner sleeve. Ascrew driver for rotating and driving the screw member into bone canalso be provided, as well as a rod insertion device including a handleand a distal gripping end for gripping and delivering a rod member.

The system can also include an anti-torque device including a handleconnected to a cannula, wherein the cannula is configured to be placedover the outer sleeve, and wherein the cannula includes a side slot forengaging the rod member. A persuader device including internal threadscan also be provided that can interact with the anti-torque device andassist in forcing the rod member into the seat of the screw member.

In other embodiments, an alternative spinal stabilization system isprovided. The system comprises an outer sleeve having a distal slot. Thesystem also comprises an inner sleeve having a proximal section and adistal section, the proximal section including a threaded portion, thedistal section including a slot and a pair of compressible graspingelements, each of the grasping elements including an internal protrudingmember. The inner sleeve can be configured to be slidably received intothe outer sleeve such that the slot of the inner sleeve is aligned withthe distal slot of the outer sleeve, and wherein sliding the outersleeve relative to the inner sleeve actuates compression of the graspingelements of the inner sleeve.

In other embodiments, a method of spinal stabilization is provided. Afirst access device can be provided that includes a first outer sleeveand a first inner sleeve, wherein the first inner sleeve includes a pairof compressible grasping elements actuated by sliding the first innersleeve relative to the first outer sleeve. A first screw member can beprovided within the first pair of compressible grasping elements. Thefirst pair of compressible grasping elements can be compressed to couplethe first access device to the first screw member. The first accessdevice and first screw member can be delivered to a first locationwithin a patient. The first screw member can be inserted into a firstbone member of the patient. A second access device can be provided thatincludes a second outer sleeve and a second inner sleeve, wherein thesecond inner sleeve includes a pair of compressible grasping elementsactuated by sliding the second inner sleeve relative to the second outersleeve. A second screw member can be provided within the second pair ofcompressible grasping elements. The second pair of compressible graspingelements can be compressed to couple the second access device to thesecond screw member. The second access device and second screw membercan be delivered to a second location within a patient. The second screwmember can be inserted into a second bone member of the patient. A rodmember can be delivered to connect between the first screw member andsecond screw member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a side view of an assembled minimally invasive toweraccess device according to embodiments of the present application.

FIG. 2 illustrates an exploded view of different components of the toweraccess device of FIG. 1 according to embodiments of the presentapplication.

FIGS. 3A-3G illustrate several views of an outer sleeve member accordingto embodiments of the present application.

FIGS. 4A-4G illustrate several views of an inner sleeve member accordingto embodiments of the present application.

FIGS. 5A-5G illustrate several views of a spring latch member accordingto embodiments of the present application.

FIGS. 6A-6E illustrate several views of a lock nut according toembodiments of the present application.

FIGS. 7A-7D illustrate several views of a screw member for using with aspring latch according to embodiments of the present application.

FIGS. 8A-8G illustrate a procedure for assembling and operating a towerdevice according to embodiments of the present application.

FIGS. 9A and 9B illustrate a rod insertion device according toembodiments of the present application.

FIGS. 10A and 10B illustrate a rod persuader device and anti-torquedevice in use according to embodiments of the present application.

FIGS. 11A-11G illustrate different views of an anti-torque deviceaccording to embodiments of the present application.

FIGS. 12A and 12B illustrate different views of a rod persuader deviceaccording to embodiments of the present application.

FIGS. 13A-13C illustrate a break-away screw delivery device according toembodiments of the present application.

FIGS. 14A-14H illustrate different views a persuader system according toembodiments of the present application.

DETAILED DESCRIPTION OF EMBODIMENTS

The present application relates to minimally invasive devices andmethods for assisting in the delivery of fixation devices and otherimplants in a patient. While the minimally invasive devices describedherein can be used to assist various treatments, in some embodiments,they are used to assist in delivering fixation devices and otherimplants to help stabilize the spine.

In some embodiments, a minimally invasive tower access device isprovided. The access device includes an outer sleeve and an inner sleevethat telescopingly or slidably engage with one another. The inner sleeveincludes one or more grasping elements that can grasp a fixation device(e.g., a pedicle screw) for delivery into a bone member of a spine. Oncethe access device is coupled to the spinal screw, the access device andspinal screw can be delivered either through an incision in an opensurgery, or minimally invasively through a relatively smaller incision,such as percutaneously. Once through the incision, the spinal screw canbe brought to a location proximate to a bone member where it can beinserted. The access device can serve as a portal or opening thatextends from the bone member to outside of the patient. Instruments canbe delivered through the access device. For example, a screw driver canbe provided through the access device to secure the spinal screw to thebone member. In addition, implants can be delivered adjacent the side ofthe access device. For example, a rod implant can be delivered along theside of the access device which can connect in between the implantedscrews. By using one or more access devices to deliver screws or otherimplants as described herein, a spinal stabilization system can beformed. The one or more access devices advantageously allow screws andother implants to be inserted in a specific location with ease, andallow for a surgeon to comfortably maintain external control of thescrew from outside of a patient's body.

A number of additional instruments can be used with the access device toprovide spinal stabilization. Among the instruments that can be usedinclude a screw driver, a rod insertion device, an anti-torque device,and a rod persuader device. These instruments, as well as the accessdevice, will be discussed in greater detail below.

Minimally Invasive Tower Access Device

FIG. 1 illustrates a side view of an assembled minimally invasive toweraccess device according to embodiments of the present application. Theaccess device 5 includes an elongated outer sleeve 21 and an elongatedinner sleeve 22 that are slidably engaged with each other. The accessdevice 5 also includes a spring latch 60 (shown in FIGS. 2 and 5). Alock nut 80 is also provided that engages with a threaded portion of theinner sleeve 22. When all of the components are assembled as shown inFIG. 1, they form an access device 5 that can couple to a fixationdevice, such as a screw. The coupled access device and screw can bedelivered to a target location of a patient. In some embodiments, theaccess device and screw member are delivered percutaneously.

FIG. 2 illustrates an exploded view of different components (e.g., theouter sleeve, inner sleeve, and lock nut) of the tower access device ofFIG. 1 according to embodiments of the present application. Each ofthese components will be discussed in greater detail below.

FIGS. 3A-3G illustrate several views of an outer sleeve member 21according to embodiments of the present application. The outer sleeve 21includes two slots, a proximal slot 27 and a distal slot 28. In otherembodiments, the outer sleeve 21 can have a single distal slot. Withinthe outer sleeve member 21 is a hollow cylindrical body through which aninner sleeve can be received.

The proximal slot 27 and distal slot 28 are formed on opposite ends ofthe outer sleeve 21—the proximal slot 27 is formed on a proximal end ofthe outer sleeve 21 while the distal slot 28 is formed on a distal endof the outer sleeve 21. As used herein, the term “proximal end” refersto the end of the access device that is closer to the end exposed duringsurgery, while the term “distal end” refers to the end of the accessdevice that is closer to a target location within a patient fordelivering a fixation device or implant. While both the proximal slot 27and the distal slot 28 are formed along an edge of the outer sleeve 21,in some embodiments, either one or both slots can be formed within thebody of the outer sleeve 21 instead of along an edge.

In some embodiments, the proximal slot 27 opens along one side of theouter sleeve 21, while the distal slot 28 opens along two sides of theouter sleeve 21 (as shown in FIG. 3A). The proximal slot 27 can belocated in between the two openings that form the distal slot 28. Whilea center longitudinal axis of the proximal slot 27 is shown at about a90 degree angle from the a center longitudinal axis of the distal slot28, the proximal slot 27 can be located at any angle relative to theopenings of the distal slot 28, such as between 0 and 90 degrees. Whilethe proximal slot 27 is smaller in both width and length than the distalslot 28 in the illustrated embodiment, the two slots need not be limitedto these relative dimensions.

Both the proximal slot 27 and the distal slot 28 of the outer sleeve 21can serve particular functions. In some embodiments, the proximal slot27 can serve to receive the spring latch 60, which can be fixed to theinner sleeve 22. The proximal slot 27 can work in conjunction with thespring latch 60 to identify the current mode of operation of the accessdevice 5 (e.g., “locked” or “unlocked” mode) as best shown in FIG. 8E.The spring latch 60 can include a marker 69 (shown in FIG. 8E) that canhelp identify the particular mode of operation. The different modes ofoperation will be discussed below. With the spring latch 60, the mode ofoperation of the access device will be easily visible to the surgeon. Inaddition, having the proximal slot 27 work in conjunction with thespring latch 60 advantageously allows for proper placement of the outersleeve 21 relative to the inner sleeve 22, such that they can havealigning distal slots when the spring latch 60 is inserted in theproximal slot 27 of the outer sleeve.

In some embodiments, the distal slot 28 can serve to receive one or morestabilization implants therethrough. For example, in some embodiments, astabilizing rod member can be delivered along the side of the accessdevice 5 and angled through the distal slot 28. Once the rod member isangled through the distal slot 28, it can be forced downward onto thehead of the screw. Then, one end of the rod member can be fixed to afirst screw, while the second end of the rod member is fixed to a secondscrew, thereby providing spinal stabilization.

The distal slot 28 of the outer sleeve 21 can have a length between 4 cmand 8 cm, or a length between 6 cm and 7 cm. In some embodiments, thelength of the distal slot 28 is much longer (e.g., at least 5.5 cm) thanslots in conventional access devices. In some embodiments, the length ofthe distal slot 28 of the outer sleeve 21 is between ⅓ and ¾, orapproximately ½ in some instances, the length of the entire body of theouter sleeve. In some embodiments, as shown in FIGS. 8H′-8J′, the distalslot 28 of the outer sleeve can be even longer, and can extend almostthe entire length of the outer sleeve 21. The advantage of the longerslot is that a rod implant can be more easily delivered through the slotto provide spinal stabilization. In addition, providing a longer slotlength makes the instrument lighter by removing material from thesystem. A challenge, however, is that with the longer slot, thesidewalls that form the slot may need to be stronger in order towithstand forces on the sidewalls in some embodiments. Accordingly, insome embodiments, the thickness of the sidewalls that form the longerdistal slot 28 of the outer sleeve 21 is preferably increased relativeto conventional sleeves to withstand forces on the sidewalls. In someembodiments, the thickness of the sidewalls that form the longer distalslot 28 is between about 0.05 cm and 0.4 cm, or between about 0.2 cm and0.3 cm.

FIGS. 4A-4G illustrate several views of an inner sleeve member 22according to embodiments of the present application. The inner sleeve 21includes a proximal section 31 and a distal section 33. The distalsection 33 includes a distal slot 23 and a pair of grasping elements 38.The inner sleeve 22 can be slidably received within the outer sleeve 21,and in some embodiments, can be secured in a position relative to theouter sleeve 21 by using the lock nut 80. Like the outer sleeve 21, theinner sleeve 22 includes a hollow cylindrical body. In some embodiments,the inner sleeve has an interior diameter of between about 0.5 cm and 2cm, or between about 1.0 cm and 1.1 cm.

In some embodiments, the proximal section 31 of the inner sleeve 22includes an exposed threaded portion 34, as shown in FIG. 1. A lock nut80 having internal threads can engage with the exposed threaded portion34 of the inner sleeve. By rotating the lock nut 80 in a clockwisedirection until it is at a bottom section of the exposed threadedportion 34, the outer sleeve 21 can be secured with the inner sleeve 22in a “locked” mode in which the compressible grasping elements 38 of theinner sleeve 21 are compressed (discussed below).

Below the proximal section 31 of the inner sleeve 22 is the distalsection 33 including a distal slot 23 and compressible grasping elements38. Like the distal slot 28 of the outer sleeve 21, the distal slot 23of the inner sleeve 22 can open on two sides of the inner sleeve 22. Insome embodiments, the distal slot 23 of the inner sleeve 22 isapproximately the same size (e.g., similar width and height) of thedistal slot 28 of the outer sleeve 21. One skilled in the art willappreciate that the dimensions of both the distal slot 28 of the outersleeve 21 and slot 23 of the inner sleeve 22 can vary with respect toone another. The distal slot 23 of the inner sleeve 22 can be placed inpart or in complete alignment with the distal slot 28 of the outersleeve 21. In some embodiments, when the distal slot 23 of the innersleeve 22 is aligned with the distal slot 28 of the outer sleeve 21, arod implant that is delivered into the patient can pass through both ofthe slots. The rod implant can be angled through the slots such thateach end of the rod implant makes contact with a screw head within theaccess device.

The distal slot 23 of the inner sleeve 22 can have a length betweenabout 4.0 cm and 8.0 cm, or between about 6.0 cm and 7.0 cm. In someembodiments, the length of the distal slot 23 is much longer (e.g., atleast 5.5 cm) than slots in conventional access devices. In someembodiments, the length of the distal slot 23 of the inner sleeve 22 isbetween 1/3 and 3/4, or approximately ½ in some instances, the length ofa non-threaded body of the inner sleeve 22.

In some embodiments, the pair of grasping elements 38 comprise a pair ofcompressible arms or tines for receiving a screw head, as shown in FIG.4A. One skilled in the art will appreciate that the shape of thegrasping elements 38 need not be limited to the description describedherein. In some embodiments, the distance from one grasping element toanother is slightly greater than the diameter of the hollow interior ofthe outer sleeve 21 in an uncompressed state. In these embodiments, inorder for the inner sleeve 22 to be received through the proximal end ofthe outer sleeve 21, the grasping elements 38 should be slightlycompressed. When the grasping elements 38 exit the distal end of theouter sleeve 21, the grasping elements 38 can return to theiruncompressed state, thereby advantageously helping to secure the innersleeve 22 to the outer sleeve 21 by limiting the inner sleeve 22 fromunintentionally backing out of the outer sleeve 21.

In some embodiments, the grasping elements 38 are flat, while in otherembodiments (as shown in FIG. 4A), the grasping elements 38 can includesome curvature so as to accommodate a screw head of a particular shape.In some embodiments, the grasping elements 38 include protruding members45 that can be received in an aperture of the screw head to secure thescrew to the inner sleeve. The protruding members 45 can be rigid orsomewhat flexible, and are configured to be inserted into two or moreholes or apertures formed on the head of a screw upon compression of thegrasping elements 38 of the inner sleeve 22. While the protrudingmembers 45 can have a smooth surface finish, in some embodiments, theprotruding members 45 have a roughened surface finish that can provide africtional force between the protruding members 45 and surfaces of thescrew head that form the receiving apertures 45. The protruding members45 can have a cross-sectional area that is circular, rectangular,trapezoidal or any other shape, so long as they are securely receivablein a corresponding aperture of the head of the screw. In someembodiments, rather than have protruding members that resemble pins, theinner sleeve 22 can include flanges that extend from a bottom surface ofthe distal end of the inner sleeve 22. The flanges can be compressiblesuch that when compressed, the flanges surround and secure a portion ofthe head of the screw (such as a bottom portion), thereby coupling theinner sleeve 22 to the screw.

In some embodiments, the compressible grasping elements 38 of the innersleeve 22 also include an internal surface 47 (shown in FIG. 4A) forengaging a slot on the screw head. The purpose of the internal surface47 is to absorb axial force that is transferred to the grasping elements38 of the inner sleeve 22 from the screw head when the screw head isunder compression. The internal surface 47 can engage one or more slotslocated on the screw head, and can comprise a substantially triangulartapered surface proximal from the protruding member 45. In someembodiments, the substantially triangular tapered surface 47 can belocated below a ledge 49 that forms an indentation in the interior ofthe grasping elements 38. The ledge 49 can advantageously provide asurface for the screw to stop against once the screw is inserted to itsproper depth within the inner sleeve 22.

In some embodiments, the grasping elements 38 include optional slits 41,which advantageously assist to provide compressibility to the graspingelements 38. The compressibility of the grasping elements 38 isadvantageous as it allows the inner sleeve to be received in the outersleeve, and also helps the grasping elements 38 to couple with a screwhead. As shown in FIG. 4A, in some embodiments, each of the graspingelements 38 can include a pair of slits 41 such that each graspingelement is divided into three sections—two side sections and a middlesection. In these embodiments, the middle section can include aprotruding member 45 and internal tapered surface 47, as discussedabove.

The inner sleeve 22 can be slidably received in the outer sleeve 21 suchthat the grasping elements 38 of the inner sleeve 22 can extend beyondthe distal end of the outer sleeve 21. In some embodiments, the innersleeve 22 can be slidably received in the outer sleeve 21 such that in afirst position, the grasping elements 38 are uncompressed. Sliding theinner sleeve 22 relative to the outer sleeve 21 in a second position canresult in compression of the grasping elements 38. For example, theouter sleeve 21 can be slid down the inner sleeve 22 such that a bottomof the outer sleeve 21 helps to compress the grasping elements 38. Insome embodiments, the outer sleeve 21 can completely cover the graspingelements 38 to compress the grasping elements, while in otherembodiments, the outer sleeve 21 only covers a portion of the graspingelements 38 to result in compression. The compression mechanism providedby the outer sleeve 21 sliding over the compressible grasping elements38 of the inner sleeve 21 is advantageous over conventional screwdelivery devices, as the body of the outer sleeve 21 helps to reduce therisk of the protruding members 45 becoming accidentally loose from thehead of the screw. Moreover, having a slidably engaged outer sleeve 21and inner sleeve 22 reduces the need for extra tools that might be usedin conventional screw delivery devices for securing an access device toa screw member. In some embodiments, the inner sleeve 22 and outersleeve 21 can work in conjunction with a lock nut 80 to secure the innersleeve 22 and outer sleeve 21 in a position such that the graspingelements are compressed. The inner sleeve 22 and outer sleeve 21 canalso work in conjunction with a spring latch 60.

FIGS. 5A-5G illustrate several views of a spring latch member 60according to embodiments of the present application. The spring latch 60includes an upper raised surface 64 and a lower raised surface 66, aswell as a tab member 68 extending from a proximal end. The spring latch60 can also include holes 76 for receiving one or more fixation members(e.g., screws) for attaching the spring latch 60 to the inner sleeve 22.

In some embodiments, and as shown in FIG. 8E, the spring latch 60 can beattached to the inner sleeve 22. The spring latch 60 can serve multiplefunctions. In some embodiments, the spring latch 60 (when fixed to theinner sleeve 22) can fit within the proximal slot 27 of the outer sleeve21 and can serve to identify the current mode of operation of the accessdevice 5 when the inner sleeve 22 and outer sleeve 21 are slid relativeto one another. For example, the spring latch 60 can include a markerthat can identify when the outer sleeve and inner sleeve are in an“unlocked” position in which the two sleeves remain slidable relative toone another. Or the spring latch 60 can identify when the outer sleeveand inner sleeve are in a “locked” position in which the two sleeves aresecured in a position with the lock nut 80. In addition, the springlatch 60 can advantageously help to ensure that the inner sleeve 22 andouter sleeve 21 are in proper alignment, by having the spring latch 60fit within the proximal slot 27 of the outer sleeve 21.

In some embodiments, the tab member 68 of the spring latch can interactwith lock nut 80 when the lock nut 80 is rotated to a distal section ofthe external threaded portion 34 of the inner sleeve. For example, thetab member 68 can interact with an inner engagement surface 83 (e.g.,one or more depressions 88 as shown in FIG. 6B) of the lock nut 80. Byfitting in one of the depressions 88, the tab member 68 canadvantageously limit unintentional counter or back rotation of the locknut 80 when in use.

FIGS. 6A-6E illustrate several views of a lock nut 80 according toembodiments of the present application. The lock nut 80 includes aninner engagement surface 83 that can engage the external threadedportion of the inner sleeve 22. In some embodiments, the innerengagement surface 83 comprises a threaded portion (not shown) thatcomplements the external threads of the inner sleeve 22. In someembodiments, the inner engagement surface 83 can also include a seriesof depressions 88 for interacting with the tab member 68 of the springlatch 60. When the lock nut 80 is placed in a downward section of thethreaded portion of the inner sleeve 22 fixed to a spring latch 60, atab member 68 of the spring latch can interact and fit into one of thedepressions 88, thereby advantageously limiting unintentional back orcounter-clockwise rotation of the lock nut 80. On the exterior of thelock nut 80, a knurled surface is advantageously provided for easygrasping during use.

The lock nut 80 can be used to secure the inner sleeve 22 and outersleeve 21 in a locked mode by adjusting the lock nut 80 in a clockwisedirection down the threaded portion of the inner sleeve 22 until it canno longer turn clockwise. In the locked mode, the inner sleeve 22 issecured in position with the outer sleeve 21, and the grasping elements38 of the inner sleeve are compressed (as shown in FIG. 8G). In thismode, a screw head or other fixation device can be grasped and securedby the compressed grasping elements 38.

FIGS. 7A-7D illustrate several views of a screw member 90 for use with aspring latch according to embodiments of the present application. Thescrew member 90 can be inserted into the holes 76 of the spring latch 60to secure the spring latch 60 to the inner sleeve 22, as shown in FIG.8E.

FIGS. 8A-8G illustrate a procedure for assembling and operating a towerdevice according to embodiments of the present application.

FIG. 8A illustrates the inner sleeve 22, outer sleeve 21 and lock nut 80as separate components.

FIGS. 8B and 8C illustrate the inner sleeve 22 inserted into the outersleeve 21. The inner sleeve 22 is slidable relative to the outer sleeve21 such that the distal, compressible grasping elements 38 of the innersleeve extend from a distal end of the outer sleeve 21. In addition, inorder to properly orient the inner sleeve 22 relative to the outersleeve 21, the spring latch 60 (fixed to the inner sleeve) can bealigned with the proximal slot 27 of the outer sleeve 21. In someembodiments, the inner sleeve 22 and outer sleeve 21 are slidablerelative to one another until the lock nut 80 is secured in place.

FIG. 8D illustrates a close-up view of the grasping elements 38 uponinsertion of the inner sleeve 22 in the outer sleeve 21 without the locknut 80. The inner sleeve 22 can be moved relative to the outer sleeve 21such that the grasping elements 38 are open and in an uncompressedstate, as shown in FIG. 8D. In the uncompressed state, the graspingelements 38 can easily fit over an object, such as a screw head. Thegrasping elements 38 can subsequently be compressed (as shown in FIG.8G) to grasp a screw member with the assistance of the lock nut 80.

FIG. 8E illustrates a close-up view of the lock nut 80 in the process ofmoving down the threaded portion 34 of the inner sleeve 22. In someembodiments, the lock nut 80 can be rotated clockwise until it ispressed firmly against the surface of the outer sleeve 21. When the locknut 80 is no longer able to rotate clockwise down the threaded portion34, the access device 5 will be in locked mode, as indicated by themarker 69 on the spring latch 60. In locked mode, the inner sleeve 22 issecured in a position relative to the outer sleeve 21, and the graspingelements 38 are compressed. In addition, in this mode, the tab member 68of the spring latch 60 engages an inner portion of the lock nut 80 andlimits counter-rotation of the lock nut. Compression of the graspingelements 38 helps to secure the access device to a screw member (e.g.,via apertures in the screw head that receive internal protruding membersof the grasping elements).

FIG. 8F illustrates a side view of the fully-assembled access device 5in locked mode. As shown in the figure, the lock nut 80 has been rotatedcompletely clockwise down the threaded portion 34 of the inner sleeve.The tab member 68 of the spring latch is now hidden from view, as it isengaged with an inner portion of the lock nut 80. In the locked mode,the grasping elements 38 are compressed (as shown in FIG. 8G) andcapable of securing a screw head therein.

The access device 5 can be coupled to a screw 90 having a head member 92and threaded shaft portion 94, as shown in FIGS. 10A and 10B. In someembodiments, the head member 92 can be tulip-shaped. The head member 92can have a U-shaped seat for receiving an implant, such as a stabilizingrod member. The head member 92 can include holes or apertures forreceiving one or more protruding members (e.g., from the distal end ofthe access device). In some embodiments, the surface of the head member92 also includes one or more slots that interact with the internaltapered surface 47 of the inner sleeve to assist in the absorption ofaxial loads.

An elongated, threaded shaft member 94 can extend from the bottom of thehead member 92. In some embodiments, the head member 92 and shaft member94 are separate components that are coupled, while in other embodiments,the head member 92 and shaft member 94 form a single unitary member. Insome embodiments, the head member 92 of the screw 90 can comprise abreak-away portion that is easily separated from the shaft member 94 bya snapping motion. The screw 90 can be cannulated such that it caninclude a hollow body through which a guidewire or k-wire can bereceived, as discussed below. Various types of screws can be used withthe access device, including different kinds of pedicle screws.

In some embodiments, once the access device 5 and screw 90 are coupled,a screw driver (not shown) can be inserted into the access device. Thescrew driver, which includes a handle and a shaft, can engage the headof the screw 90 (e.g., a hex portion of the screw). The screw driver canbe cannulated such that it too can receive a guidewire or k-wire thatpasses through the cannulated screw.

The coupled access device 5 and screw 90 (along with the screw driver)can be inserted percutaneously to a target location within the patient(e.g., a portion of a spine) wherein the screw is to be delivered. Thecoupled access device 5 and screw 90 can be guided using a guide-wire ork-wire that is insertable through the hollow body of the screw 90. Oncethe screw 90 is placed proximal to a target location, the screw 90 canbe driven into the location by using the screw driver to providerotational and axial force. In some embodiments, rotation of the screwdriver causes rotation of the screw 90, as well as rotation of theaccess device 5 to which it is coupled.

One or more screws can be fixed into bone using the devices describedabove. For example, in one embodiment, a first screw attached to a firstaccess device can be delivered into a first vertebrae, while a secondscrew attached to a second access device can be delivered into a secondvertebrae. Once the screws are fixed into bone, an implant, such as aconnecting rod member (not shown), can be delivered in the patient andconnected between the two screws. In some embodiments, the rod member isdelivered via a mini-open procedure, in which an incision is madebetween the first and second screw. In other embodiments, the rod memberis delivered percutaneously along the side of either the first andsecond access devices. One end of the rod member can be fixed to thefirst screw, while the opposite end of the rod member can be fixed tothe second screw, thereby forming a stabilizing connection between thescrews. To enclose and secure the ends of the rod member to the screws,cap screws (not shown) can be provided through the access devices andover the rod ends. In some embodiments, the cap screws are threaded.Each cap screw can provide a downward force on a rod end, and thisdownward force can be transferred from the rod end to the screw head,thereby providing a secure locking mechanism for the system.

To assist in providing and securing the ends of the rod member to thescrew heads, a number of different components can be provided. Among thecomponents are a rod insertion device, an anti-torque device and apersuader device, examples of which are described below.

Rod Insertion System—Rod Insertion Device, Anti-Torque Device andPersuader Device

A rod insertion system is provided that can assist in the delivery of arod implant to a desired location within a patient. The rod insertionsystem can include a rod insertion device 110, an anti-torque device142, and a persuader device 131.

FIGS. 9A and 9B illustrate a rod insertion device 110 according toembodiments of the present application. The rod insertion device 110includes a distal gripping end 115, a sliding sleeve 118, a torquedriven locking cap 121 and a handle 130.

The rod insertion device 110 includes a distal gripping end 115 forgripping a rod member so that it can be delivered into a patient. Thegripping end 115 can be affixed to a shaft member of the rod insertiondevice 110. The shaft member can have a longitudinal axis that runs alength between the gripping end 115 and the handle 130. The distalgripping end 115 comprises two or more gripping elements (e.g., fingersor tines) that can be used to grip and hold a rod member. The grippingelements can be tapered. The gripping elements can also be compressibleso as to securely grip a rod member to allow for delivery of the rodmember into a patient. In some embodiments, the gripping elements arecompressed by sliding the sliding sleeve 118 downward over a portion ofthe gripping end 115.

The sliding sleeve 118 can be located over a portion of the shaft memberattached to the gripping end 115. The sliding sleeve 118 can be slidablerelative to the inner shaft member. In some embodiments, upon slidingthe sleeve 118 distally over a portion of the gripping end 115, thegripping end 115 can be compressed. When the gripping end 115 iscompressed, it can grip or grasp a rod member or other implant. In someembodiments, the sliding sleeve 118 is actuated by rotating an adjacenttorque driven locking cap 121.

The torque driven locking cap 121 is provided adjacent the slidingsleeve 118 on the rod insertion device 110. The torque driven lockingcap 121 can work similar to the lock nut 80; that is, it can be rotatedclockwise until it contacts and secures the sliding sleeve 118 in aposition whereby the gripping end 115 is compressed. In someembodiments, the torque driven locking cap 121 includes a knurledexterior surface that allows for easier gripping.

At the proximal end of the rod insertion device 110 is a handle 130. Thehandle can include dimples or grooves to allow for easy handling of therod insertion device 110.

In some embodiments, the rod insertion device 110 in FIGS. 9A and 9B canbe used to deliver a rod implant adjacent to the sidewalls of an accessdevice 5. In other embodiments, the rod insertion device 110 can be usedto deliver a rod implant through an incision in a mini-open procedurebetween two access devices.

FIGS. 10A and 10B illustrate an anti-torque device 142 and rod persuaderdevice 131 in use together according to embodiments of the presentapplication. As shown in the figures, the anti-torque device 142 can beplaced over the outer sleeve of the access devices, while the rodpersuader device 131 can be placed above the anti-torque device and overa proximal threaded portion of the inner sleeve 21. In some embodiments,either one or both of these instruments are optional.

FIGS. 11A-11G illustrate different views of an anti-torque device 142according to embodiments of the present application. The anti-torquedevice 142 comprises a handle 143 operably connected to a cannula 145.In some embodiments, the cannula 145 is configured to operate over theouter sleeve 21 of the access device 5. At the distal end of the cannula145 is a slot 149 that can interact with a rod member that has beeninserted in a patient but is not in a proper position. In someembodiments, the slot 149 of the anti-torque device can press downagainst the rod member, thereby helping to force the rod member into adesired position within a patient. In some embodiments, the slot forms ahalf-circle with a radius of between about 0.1 cm and 0.5 cm, or betweenabout 0.3 cm and 0.4 cm.

The anti-torque device 142 can provide a number of advantages. Oneadvantage of the anti-torque device 142 is that it can act as apersuader to force a rod member into a desired position within apatient, as noted above. Another advantage of the anti-torque device 142is that it can provide an anti-torque mechanism that resists rotation ofthe access device 5 when adjusting the position of a rod member. Forexample, when trying to adjust the rod member into a desirable position,the anti-torque device 142 can help to ensure that the access device 5is not rotated. In addition, in some embodiments, the distal end of theanti-torque device 142 preferably helps to hold the screw 90 in a secureposition while a cap screw is tightened over a rod member and screwhead.

FIGS. 12A and 12B illustrate different views of a rod persuader device131 that is configured to fit above the anti-torque device 142 and overa threaded portion of the inner sleeve 22 of the access device 5. Insome embodiments, the rod persuader device 131 comprises a substantiallycylindrical member that includes a hollow interior 136. In someembodiments, the rod persuader device 131 can included internal threads(not shown) which are capable with mating with the threaded portion ofthe inner sleeve 22. The rod persuader device 131 can be configured tobe placed in contact with the anti-torque device 142 by rotating thepersuader device 131 clockwise down the exposed threaded portion of theinner sleeve 22. The rod persuader device 131 can apply a downward forceon the anti-torque device 142, which can then transfer to a rod member.This force helps to advantageously stabilize the rod member and place itin a desirable position within the patient's body. The rod persuaderdevice 131 is also advantageous in that it is clearly visible outside ofthe patient's body, and provides a comfortable means to transmit forceto stabilize and position the rod member.

In some embodiments, the persuader device 131 is optional, and can beused on its own or with the anti-torque device 142 to force a rod memberinto a desired location within an access device 5 (e.g., onto a seat ofa screw head). In some embodiments, the anti-torque device 142 and/orpersuader device 131 can be used to displace blocking tissue that mayprevent the rod member from being placed in a desired location. Both theanti-torque device 142 and persuader device 131 are uniquely configuredsuch that they can be used on top of the access device 5. Thisconfiguration allows a user (e.g., surgeon) of the anti-torque deviceand/or persuader device 131 to displace tissue and deliver the rodmember into its proper position with ease, as the user would only haveto apply relatively minor force to rotate the persuader device tointeract with the anti-torque device. In addition, in some embodiments,the anti-torque device 142 and/or persuader device 131 includes an upperviewing window, such that the user can easily visualize tissue and rodmember position within the access device 5.

Methods of Using the Access Device and Rod Insertion System

A procedure for using the minimally invasive access device according toembodiments of the present application will now be described. Theprocedure makes use of a first minimally invasive tower access deviceand a second minimally invasive tower access device. The access deviceincludes an outer sleeve slidable relative to an inner sleeve, as wellas a lock nut. The inner sleeve includes a pair of compressible graspingelements each having an internal protruding member to be received in anaperture of a screw head.

The first access device is provided with its distal grasping elements inan uncompressed state. A first screw having a screw head with aperturesis also provided. The first screw can be placed such that its screw headis in between the uncompressed grasping elements. The access device canbe attached to the screw head by compressing the grasping elements. Thegrasping elements are compressed by sliding the outer sleeve relative tothe inner sleeve, and rotating the lock nut clockwise down a threadedportion of the inner sleeve. Upon compression of the grasping elements,the internal protruding members of the inner sleeve will be insertedinto corresponding apertures of the screw head, thereby coupling theaccess device to the screw.

After coupling the access device to the screw, a screw driver can beprovided. The screw driver, which includes a handle portion and a shaftportion, can be delivered down the access device until the shaft portionis in contact with the head of the screw. The coupled access device andscrew, as well as the screw driver, are ready to be delivered through anincision.

In some embodiments, an incision of a desirable size is formed byproviding a k-wire or guidewire that guides a dilator. The dilatorincludes one or more expandable sleeves, and can assist in providing anopening of a desirable size for inserting the coupled access device andscrew into a patient.

The coupled access device and screw can be percutaneously delivered to alocation (e.g., using a k-wire) such that the screw can be driven into abone (e.g., a pedicle). The screw driver can provide rotational andaxial driving forces to drive the screw into bone. Once the screw isdriven into the bone, the screw driver can be removed. The access deviceremains coupled to the screw such that a portion of the access deviceremains accessible to a surgeon from outside of the patient.

A second access device can now be provided, along with a second screw.All of the steps above—coupling the access device to the screw,inserting a screw driver in the access device, delivering the coupledaccess device and screw to a location within a patient through anincision, driving the screw into a bone member, and removing the screwdriver to leave only the coupled access device and screw—can be repeatedwith respect to the second access device.

A rod member can now be provided which will serve as a connecting,stabilizing member between the first and second screws. The rod membercan be delivered using a rod insertion device. The rod member can bedelivered along the outer sidewall of the first access device. The rodmember can be delivered at an angle such that its first end is receivedinto a distal slot of the first access device. The rod member can thenbe directed such that its second end is received into a distal slot ofthe second access device. The first end of the rod member can then beconnected to the first screw within the first access device, while thesecond end of the rod member can then be connected to the second screwwithin the second access device. A screw cap can then be delivered downeach of the access sleeves, and can be used to impart a downward forceon the rod member to secure the rod member in the spinal stabilizationsystem.

To ensure proper placement of the rod member within the access sleeves,an optional anti-torque device can be provided. The anti-torque deviceincludes a cannula having a slot. The cannula can be placed over eitherthe first or second access devices, and the slot on the cannula can beused as a persuader to force the rod member into a desired positionwithin the patient. Simultaneously, while serving as a persuader, theanti-torque device can also limit undesirable rotation of the accessdevices that can be caused during adjustment of the rod member. In someembodiments, the anti-torque device helps to secure the screw inposition while a screw cap imparts a downward force on the rod memberthat transfers to the screw head.

In addition to the anti-torque device, an optional rod persuader devicecan also be provided to interact with the anti-torque device. The rodpersuader device can be placed above the anti-torque device, and can beinserted over a threaded portion of the inner sleeve. The anti-torquedevice and persuader device can help to displace tissue that may blockthe proper placement of the rod member within an access device. Theanti-torque device and persuader device can help to force the ends ofthe rod members into a seat of the first and second screw heads, therebycreating a spinal stabilization member between the two screws.

Once the rod member is placed in a desired position between the twoscrews (e.g., either with or without the anti-torque device and/orpersuader device), screw caps can be provided down the access devicesthat secure the ends of the rod member to the heads of the screws. Oncethe screw caps are provided, the first and second access devices can beremoved. Alternatively, the first or second access devices can be keptin place so that the steps above can be repeated using additionaldevices. It would then be possible to provide additional rod implantsacross bone members, thereby creating a spinal stabilization system. Insome embodiments, a spinal stabilization system comprises two, three,four, or more rod implants.

Once the access devices are removed, the patient can then be allowed toheal. Advantageously, with the use of the access devices describedherein, the recovery time is reduced compared to conventional surgeriesdue to the relatively minimal incisions needed to perform the surgery.

Additional Embodiments of Devices

In addition to the embodiments of devices described above that can beused with minimally invasive surgeries, other devices are described thatcan also be used to assist in spinal stabilization. Many of thesedevices can be used with open or mini-open surgeries, as will bediscussed below.

FIGS. 13A and 13B illustrate a break-away screw delivery deviceaccording to embodiments of the present application. The break-awayscrew delivery device 200 comprises an elongated portion 205 having anelongated slot 228. Along the length of the device 200 are grooves orindentations 209 that help to identify and facilitate break-away pointsas will be discussed below. The elongated portion 205 is connected to ascrew portion 290 which includes a shaft 294.

In some embodiments, the break-away screw delivery device 200 can beused on its own to deliver a screw portion 290 into a bone member. Whileit is possible that the device 200 can be used percutaneously, thedevice 200 can also be used in an open surgery or mini-open surgicalprocedure. In operation, the device 200 can be delivered to a locationwithin a patient's body. When the device 200 is at a desirable location,the screw portion 290 can be driven into a bone member. In someembodiments, the screw portion 290 is driven into a bone member byproviding a screw driver through the interior of the delivery device200. Once the screw portion 290 is driven into a bone member, a rodmember can be inserted into the delivery device 200. The rod member canbe used as a connection in between two or more delivery devices 200.Afterwards, a screw cap can be provided to secure the rod member.

Advantageously, at any time, a portion of the elongated portion 205 ofthe delivery device 200 can be broken off or snapped off, for example,proximate to the indentation 209. When a portion of the elongatedportion 205 is snapped off, a distal end 211 of the elongated portion205 remains. The distal end 211 resembles the head of a screw and cansecurely receive a stabilizing rod implant. In some embodiments, aportion of the elongated portion 205 is snapped off after driving thescrew portion 290 into a bone, delivering a rod member and providing asecure screw cap. The snapped off portion of the elongated portion 205can be removed, thereby leaving within the patient a part of a bonestabilizing system.

FIGS. 14A-14H illustrate different views of an alternate persuadersystem according to embodiments of the present application. Like thebreak-away screw delivery device 200, the persuader system 231 can beused in an open procedure or mini-open procedure. The persuader system231 includes a persuader sleeve 233 that is operably connected to aninner sleeve 222 having grasping elements 238 and an outer sleeve 221.The inner sleeve 222 and outer sleeve 221 can be slidable relative toone another. The persuader sleeve 233 further includes a proximalportion 235 having a handle 237 that serves as an actuating element anda distal portion 232 having a cut-out portion 234.

In some embodiments, the persuader system 231 can be used to deliver animplant, such as a rod member, to a desirable location in a patientduring open surgery. The persuader system 231 can include an innersleeve 222 and outer sleeve 221 that are slidable relative to oneanother. The sleeves can operate similarly to the inner sleeve and outersleeve of the access device described above in that sliding the sleevesrelative to one another can result in compression of the graspingelements 238, thereby allowing a rod implant to be grasped therebetween.Once a rod implant is grasped, the persuader system 231 can be deliveredto a desirable location within a patient. In some embodiments, byactuating the handle 237 of the persuader system (e.g., by rotation),the distal portion 232 of the persuader system can be extended until thecut-out portion 234 is in contact with the rod member. Advantageously,the cut-out portion 234 can help to stabilize and secure the rod memberin a desirable position within the patient.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present embodimentswithout departing from the scope or spirit of the advantages of thepresent application. Thus, it is intended that the present applicationcover the modifications and variations of these embodiments and theirequivalents.

What is claimed is:
 1. A method of spinal stabilization, comprising:providing a first access device including a first outer sleeve and afirst inner sleeve, wherein the first inner sleeve includes a first pairof compressible grasping elements actuated by sliding the first innersleeve relative to the first outer sleeve; providing a first screwmember within the first pair of compressible grasping elements;compressing the first pair of compressible grasping elements to couplethe first access device to the first screw member; delivering the firstaccess device and first screw member to a first location within apatient; inserting the first screw member into a first bone member ofthe patient; providing a second access device including a second outersleeve and a second inner sleeve, wherein the second inner sleeveincludes a second pair of compressible grasping elements actuated bysliding the second inner sleeve relative to the second outer sleeve;providing a second screw member within the second pair of compressiblegrasping elements; compressing the second pair of compressible graspingelements to couple the second access device to the second screw member;delivering the coupled second access device and second screw member to asecond location within a patient; inserting the second screw member intoa second bone member of the patient; and delivering a rod member toconnect between the first screw member and second screw member.
 2. Themethod of claim 1, further comprising providing a screw driver withinthe first access device prior to delivering the first access device andfirst screw member to the first location within the patient.
 3. Themethod of claim, 2, wherein the first access device and first screwmember are delivered to the first location within the patient via ak-wire.
 4. The method of claim 1, further comprising providing ananti-torque device, the anti-torque device including a handle connectedto a cannula configured to be placed over the first outer sleeve.
 5. Themethod of claim 4, further comprising placing the cannula of theanti-torque device over the first outer sleeve.
 6. The method of claim5, further comprising providing a persuader device and inserting thepersuader device within an interior of the first inner sleeve to forcethe rod member into a seat of a head of the first screw member.